Question: Who was Paul Krugman's main influence ?
Paraphrase: Who is the main influence of Paul Kruman?
SPARQL (Wikidata):  select distinct ?obj where { wd:Q131112 wdt:P737 ?obj . ?obj wdt:P31 wd:Q5 } 
Answer: Paul Samuelson, John Richard Hicks, James Tobin, Arthur Cecil Pigou, Rudi Dornbusch, Hyman Minsky, John Maynard Keynes, Joseph E. Stiglitz, Isaac Asimov, John Stuart Mill